In multiple spindle screw machines, there are two distinct conditions that require machine shut-down. The first is a failure to properly turn the workpiece at any station and the second is the inadvertent disengagement of a part at any station. An automatic shut-down system for these conditions is desirable because it is difficult for a single operator to immediately view both of these conditions at all stations, frequently six or eight in number. It is possible to have two systems at each station to accomplish these tasks, such as a gauge to measure part diameter and a separate sensing barrier to detect part disengagement, but such systems are costly and hence tool buyers do not usually select these systems, particularly in cases where great precision is not required.
However, they both remain significant problems because they result in a high number of damaged parts if not detected immediately, and also broken tools.
Thus, it is a primary object of the present invention to ameliorate the problems noted above in systems for detecting conditions in two directions.